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diff --git a/contrib/bind/doc/bog/types.me b/contrib/bind/doc/bog/types.me new file mode 100644 index 0000000..9d14111 --- /dev/null +++ b/contrib/bind/doc/bog/types.me @@ -0,0 +1,163 @@ +.\" ++Copyright++ 1986, 1988, 1995 +.\" - +.\" Copyright (c) 1986, 1988, 1995 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" - +.\" Portions Copyright (c) 1993 by Digital Equipment Corporation. +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies, and that +.\" the name of Digital Equipment Corporation not be used in advertising or +.\" publicity pertaining to distribution of the document or software without +.\" specific, written prior permission. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL +.\" WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT +.\" CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL +.\" DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR +.\" PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS +.\" ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS +.\" SOFTWARE. +.\" - +.\" --Copyright-- +.\" +.\" @(#)types.me 6.3 (Berkeley) 9/19/89 +.\" +.sh 1 "Types of Zones" +.pp +A ``zone'' is a point of delegation in the DNS tree. It contains all names +from a certain point ``downward'' except those which are delegated to other +zones. A ``delegation point'' has one or more \fINS\fP records in the +``parent zone'', which should be matched by equivalent \fINS\fP records at +the root of the ``delegated zone'' (i.e., the ``@'' name in the zone file). +.pp +Understanding the difference between a ``zone'' and a ``domain'' is crucial +to the proper operation of a name server. As an example, consider the +\s-1DEC.COM\s+1 \fIdomain\fP, which includes names such as +\s-1POBOX1.PA.DEC.COM\s+1 and \s-1QUABBIN.CRL.DEC.COM\s+1 even though +the \s-1DEC.COM\s+1 \fIzone\fP includes only \fIdelegations\fP for the +\s-1PA.DEC.COM\s+1 and \s-1CRL.DEC.COM\s+1 zones. A zone can map exactly +to a single domain, but could also include only part of a domain (the rest +of which could be delegated to other name servers). Technically speaking, +every name in the DNS tree is a ``domain'', even if it is ``terminal'', that +is, has no ``subdomains''. Technically speaking, every subdomain is a domain +and every domain except the root is also a subdomain. The terminology is not +intuitive and you would do well to read RFC's 1033, 1034, and 1035 to gain a +complete understanding of this difficult and subtle topic. +.pp +Though \s-1BIND\s+1 is a \fIDomain\fP Name Server, it deals primarily in terms +of \fIzones\fP. The \fIprimary\fP and \fIsecondary\fP declarations in the +\fInamed.boot\fP file specify \fIzones\fP, not \fIdomains\fP. When you ask +someone if they are willing to be a secondary server for your ``domain'', you +are actually asking for secondary service for some collection of \fIzones\fP. +.pp +Each zone will have one ``primary'' server, which loads the zone contents +from some local file which is edited by humans or perhaps generated +mechanically from some other local file which is edited by humans. Then +there will be some number of ``secondary'' servers, which load the zone +contents using the \s-1IP/DNS\s+1 protocol (that is, the secondary servers will +contact the primary and fetch the zone using \s-1IP/TCP\s+1). This set of +servers (the primary and all of the secondaries) should be listed in the +\fINS\fP records in the parent zone, which will constitute a ``delegation''. +This set of servers must also be listed in the zone file itself, usually +under the ``@'' name which is a magic cookie that means the ``top level'' +or ``root'' of current zone. You can list servers in the zone's +top-level ``@'' \fINS\fP records that are not in the parent's \fINS\fP +delegation, but you cannot list servers in the parent's delegation that are +not present in the zone's ``@''. Any servers listed in the \fINS\fP records +must be configured as authoritative (either primary or secondary) for the +zone. If a server listed in a \fINS\fP record is not authoritative, it +will respond with a ``lame delegation'' when queried. +.sh 1 "Types of Servers" +.pp +Servers do not really have ``types''. A server can be a primary for some +zones and a secondary for others, or it can be only a primary, or only a +secondary, or it can serve no zones and just answer queries via its ``cache''. +Previous versions of this document referred to servers as ``master'' and +``slave'' but we now feel that those distinctions \(em and the assignment of +a ``type'' to a name server \(em are not useful. +.sh 2 "Caching Only Server" +.pp +All servers are caching servers. This means that the server caches the +information that it receives for use until the data expires. A \fICaching +Only Server\fP is a server that is not authoritative for any zone. This +server services queries and asks other servers, who have the authority, for +the information needed. All servers keep data in their cache until the data +expires, based on a \fITTL\fP (``Time To Live'') field which is maintained +for all resource records. +.sh 2 "Remote Server" +.pp +A Remote Server is an option given to people who would like to use +a name server from their workstation or on a machine that has a limited +amount of memory and CPU cycles. +With this option you can run all of the networking programs that use +the name server without the name server running on the local machine. +All of the queries are serviced by a name server that is running on another +machine on the network. +A host which has an +\fI/etc/resolv.conf\fP file listing only remote hosts, and which does not +run a name server of its own, is sometimes called a Remote Server (because +the actual server is remote?) but more +often it is called simply a DNS Client. +This kind of host is technically not a ``server'', +since it has no cache and does not answer queries. +.sh 2 "Slave Server" +.pp +A Slave Server is a server that always forwards queries it cannot +satisfy from its cache, to a fixed list of \fIforwarding\fP servers +instead of interacting +with the name servers for the root and other domains. +The queries to the \fIforwarding servers\fP are recursive queries. +There may be one or more forwarding servers, and they are tried in turn +until the list is exhausted. +A Slave and forwarder configuration is typically used when you do not +wish all the servers at a given site to interact with the rest +of the Internet servers. A typical scenario would involve a number of +workstations and a departmental timesharing machine with Internet +access. The workstations might be +administratively prohibited from having Internet access. +To give the workstations the appearance of access to the Internet +domain system, the workstations could be Slave servers to the timesharing +machine which would forward the queries and interact with other +name servers to resolve the query before returning the answer. +An added benefit of using the forwarding feature is that the central +machine develops a much more complete cache of information that +all the workstations can take advantage of. The use of Slave mode +and forwarding is discussed further under the description of +the \fInamed\fP bootfile commands. +.pp +There is no prohibition against declaring a server to be a \fIslave\fP +even though it has \fIprimary\fP and/or \fIsecondary\fP zones as well; +the effect will still be that anything in the local server's cache or +zones will be answered, and anything else will be forwarded using the +\fIforwarders\fP list. |
